A power supply may include multiple power transistors to generate a plurality of phase currents, inductors to conduct the phase currents, and a summing node where an output voltage is established.
Mismatches in duty cycles of the power transistors, resistances of the inductors, operating characteristics of the power transistors, and/or board traces, may result in phase current imbalances, which may lead to saturation of the inductors.
A power supply may include an analog or digital regulator to control the duty cycles to balance the phase currents with respect to one another.
Conventional digital voltage regulators include per-phase analog-to-digital converters (ADCs) to digitize measured phase currents. Outputs of the ADCs may be combined to generate digital indications of a total current and a per-phase average phase current. Per-phase digital error indications may be determined as a difference between the per-phase average phase current and corresponding ADC outputs. The digital error indications and the digital indications of the total current may be provided to a control system to regulate the duty cycles.
Since the digital indication of the total current is obtained from ADC samples of the phase currents, if the power supply is subjected to a step load, the total current indication may not be updated until a subsequent ADC sample cycle, which may correspond to a subsequent duty cycle. As a result, subsequent processes that utilize the total current indication may have delayed responses to transients. In addition, per-phase ADCs consume relatively significant amounts of area and power.
In the drawings, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears.